This invention relates generally to in-line fluid flow check valves or back flow preventers, and more particularly concerns an improved construction which positions the closure member support downstream of the checked orifice, thereby enhancing fluid flow capabilities through reduced pressure drop.
In-line poppet type check valves currently in use of the type disclosed in U.S. Pat. Nos. 2,918,083, and 2,928,416, employ poppet and/or cooperating seat constructions which during the non-check or flow condition, result in highly turbulent flow regimes downstream of the flow checked orifice. As those skilled in the art will readily recognize these highly turbulent regimes result in greatly increased pressure drop through the check valve, sometimes requiring an increase in diameter in order to achieve an acceptable flow characteristic in a given application.
The check valve of the invention disclosed here overcomes many of the pressure drop problems of currently used units, and demonstrates substantially decreased pressure drop or increased flow capability. The improvement demonstrated by the valve of this invention is achieved through positioning the poppet closure member, poppet stem support, and closure spring downstream of the checked orifice. Applicant has discovered that proper placement of the poppet and associated support elements adjacent the downstream flow areas establishes an elementary convergent/divergent flow passage resulting in substantially reduced pressure drop in the unchecked or open positions.
Accordingly, it is the object of this invention to provide an in-line poppet type check valve or back flow preventer wherein pressure drop through the valve in its unchecked or open position is substantially less than units in current use.
It is a further object of this invention to provide an in-line check valve utilizing a coaxial poppet closure member coacting with a seat seal wherein the seat seal is retained during high flow conditions by an angularly oriented seal groove.
It is a further object of this invention to provide an in-line check valve of the poppet type wherein the poppet stem support acts as an anti-turbulent baffle downstream of the checked orifice.
It is an additional object of this invention to integrate into the assembled valve a secondary sealing feature by metal-to-metal contact between the insert assembly and body.